In 2009 Bell's infrastructure did not support ADSL2+, while the modems NCF sold then, the Thompson SpeedTouch 516 and 585s, did. Because the modems defaulted to ADSL2+ and not the ADSL1 then in use on Bell's networks the modems would not connect. To fix this problem a number of modems shipped at that time were configured by NCF to force them into ADSL1 mode, which solved the problem. Now that Bell's infrastructure requires ADSL2+ for 15 Mb/s service these modems that were configured that way will not work with 15 Mb/s service unless reconfigured.

The configuration cannot be fixed by doing a factory reset, instead it must be done by Telnet into the modem and changing it via command line. Fortunately this is easy to do.